1. Field of the Invention
This invention relates to a pattern sewing machine and, more particularly, to a sewing machine which can resume, when a trouble occurs during sewing of a continuous pattern consisting of a plurality of partial patterns, sewing from the head of the partially completed pattern at the point where sewing was interrupted.
2. Description of Related Art
Embroidery sewing machines, as pattern sewing machines manufactured in recent years, include an embroidery frame for removably mounting a workpiece thereon, a driving apparatus for driving the embroidery frame to move in the X and Y directions independently of each other, a controlling apparatus for controlling the driving mechanism in accordance with embroidery stitch data, and a ROM card in which embroidery stitch data of a large number of embroidery patterns are stored. Embroidery stitch data of a selected embroidery pattern are read from the ROM card and the driving mechanism is controlled in accordance with the embroidery stitch data thus read to sew the selected embroidery pattern. Each of the embroidery patterns is normally composed of a plurality of partial embroidery patterns, each of which is sewn in the same color with the same thread. Therefore, in the embroidery data of each embroidery pattern, a sewing order of the plurality of partial embroidery patterns is set in advance.
For example, an embroidery pattern of an elephant caricature, as shown in FIG. 11, is composed of 5 partial embroidery patterns comprising a face part 100, a pair of ears 102, a cap 102, a top portion 103 of the cap and a pair of eyes and eyebrows and a profile line 104. The embroidery stitch data for the embroidery pattern includes data for the parts 100 to 104. The sewing order of the embroidery pattern is such that the partial embroidery patterns 100, 101, 102, 103 and 104 are successively sewn in order from the left to the right as shown in FIG. 11. In the case of an embroidery pattern of a large size, up to 30 to 60 minutes are required for sewing the pattern. If the needle thread is broken during sewing on such an embroidery sewing machine, a thread break detector operates so that the sewing machine is stopped automatically. However, sewing proceeds by 10 stitches or so before the sewing machine is stopped.
A stitch pattern sewing machine is disclosed in U.S. Pat. No. 4,413,574 wherein, when the needle thread is broken and sewing is to be resumed after re-threading of the needle thread, sewing is resumed from the embroidery data at a stitch a predetermined number of stitches (for example, about 100 stitches) prior to the stitch at which the sewing machine was stopped.
In addition, an electronically controlled stitch pattern sewing machine is disclosed in Japanese Patent Application Laid-Open No. Sho 57-25882 wherein, in order to eliminate a pattern selecting operation upon the interruption of sewing, sewing is resumed from the head of the continuous pattern, the sewing of which was interrupted, in response to a one-point signal designating a continuous pattern, a rest signal representative of a rest condition of the sewing machine and a starting instruction signal.
A further stitch pattern sewing machine is also known wherein, when the operator comes aware of an error in the color of the thread or the consumption of the bobbin thread and operates a start/stop switch to stop the sewing machine and later resumes sewing, sewing is either resumed from the embroidery stitch data at a stitch a predetermined number of stitches prior to the stitch at which the sewing was stopped, as described above, or sewing is resumed, in response to operation of a head search key, from the head of the embroidery pattern.
When sewing is to be resumed after interruption of sewing due to a break of the needle thread or the like, it does not substantially matter if sewing is resumed, based on embroidery stitch data, at a stitch that is a predetermined number of stitches prior to the stitch where sewing stopped. However, in such a case wherein consumption of the bobbin thread has been overlooked for a few minutes, incomplete sewing may proceed by 100 stitches or more. In this case, the embroidery pattern cannot be completed even if sewing is resumed based on the embroidery stitch data at the stitch that is the predetermined number of stitches prior to the stitch where sewing stopped.
Accordingly, the head search key must be operated to resume sewing from the head of the embroidery pattern, and consequently, the embroidery pattern portion sewn prior to the interruption is quite wasteful as those stitches must be removed by hand. The loss is particularly serious when sewing is interrupted after sewing of more than one half the embroidery pattern.
Further, also with the stitch pattern sewing machine disclosed in Japanese Patent Application Laid-Open No. Sho 57-25885, when sewing is to be resumed after interruption of pattern sewing, sewing is only resumed from the head of the continuous pattern. Sewing cannot be resumed from the head of one of the partial patterns that constitute the continuous pattern. Also in this instance, sewing is resumed from the head of the continuous pattern in a manner similar to the operation in response to the head search key described above, and consequently, the pattern portion sewn prior to the interruption is quite wasteful.